A method called direct printing is widely known. According to this method, a printer and a digital camera are connected directly via a USB or other interface, and images recorded on a recording medium in the digital camera are printed using the printer. Since this method allows images to be printed without using a personal computer, it is widely accepted as a simple printing method.
However, the brightness and color tone of the generated images vary with the manufacturer and model of the digital camera, and the brightness and color tone of the printed images vary with the model of the printer. Therefore, there are often differences between the image that the user wants and the image actually printed by the printer.
To deal with this problem, Japanese Patent Laid-Open No. 2002-314724, for example, discloses a method described below. Namely, an image file is generated on a camera, where the image file contains image processing control data consisting of parameters such as brightness and contrast set before photo-taking, as well as image data obtained by photo-taking. Then the image data is printed, based on the image processing control data, to produce an image according to the user's preferences from an image output apparatus.
Also, Japanese Patent Laid-Open No. 2004-255609, for example, discloses a method described below. Namely, a control panel of a printer called a photo direct printer is presented on a display unit such as a liquid crystal panel of a digital camera, where the control panel of the photo direct printer allows the user to make settings for image correction and the like. Next, information equivalent to information specified by directly operating the control panel of the photo direct printer is specified using the control panel presented on the digital camera and transmitted from the digital camera to the printer.
With recent increases in the pixel counts of digital cameras, the size of an image file has been increasing such that an image file created by a digital camera with an effective pixel count of millions of pixels can sometimes result in megabytes of data. With a technique disclosed in Japanese Patent Laid-Open No. 2002-314724, when a user changes image processing control data after taking a picture, the image file is loaded onto the camera memory once and updated based on the changed image processing control data to create an image file again. The time required for this process depends on the CPU performance of the digital camera. Also, longer processing time is required as the image file size increases with increases in the pixel count. Besides, memory for use in loading the sensed image is also needed, and the file size and pixel count will be limited depending on the amount of memory.
With the recent spread of direct printing, it has become possible to print easily by directly connecting a digital camera not only with a photo direct printer, but also with any of various models of printer, ranging from low-end models to high-end models. However, Japanese Patent Laid-Open No. 2004-255609 does not disclose how the digital camera acquires information as to what functions the connected printer has and what settings are available. For example, when the digital camera is connected to a low-end printer and information specified on the control panel of the camera includes a setting of functions which the low-end printer does not have, if printing is performed on the connected printer based on the information specified on the camera, it is extremely difficult for the user to tell whether the settings are not reflected or do not have much effect if reflected.
According to a direct print protocol such as PictBridge, printing is performed as a print job containing print conditions, such as the images to be printed and the type and size of paper, is sent to the printer. By utilizing this function, it is conceivable to add image processing control data such as what is described in Japanese Patent Laid-Open No. 2002-314724 to the print conditions in the print job for notifying the printer of the data. However, as items of the image processing control data increase with expansion in the functionality of printers, the image processing control data itself increases in volume. Besides, when multiple images are printed, image processing control data for the multiple images is added to the print job, resulting in an increase in the size of the print job. Consequently, the printer must hold the large amount of data it receives, requiring a large amount of memory. This obstructs the ongoing size and cost reductions of printers.